Door handle
[6] Subsequently Roman domuses and insulae incorporated lockable doors of a different design but also opened by a combined handle/key.
Houses were almost always occupied so most lockable doors would feature a sliding bolt or a drop-in bar that allowed the building to be locked from the inside.
[8] Doors excavated from Lake Nemi and dated to around 1st century CE feature knob-shaped handles.
[12] Taking the form of a ring or strip, these handles could be elaborate and decorated but were universally made of metal.
It can be speculated that since the task of making door hardware fell to the blacksmith, the use of turned or carved wooden knobs was not convenient.
A finger hole could be made that allowed the user to raise the latch from the other side of the door.
[16] From the 18th century, a wide variety of lever handles and knobs started to be produced, with designs determined by local aesthetic preference and technology.
[20] From the early 20th century architects and designers started to take serious interest in door handles as part of a comprehensive vision of spaces for living.
[22] Peter Behrens, Walter Gropius and Antoni Gaudi all produced handle designs, many of which continue to be manufactured.
These may be plain or fancy, embellished in any form, and serve variously to protect surrounding surfaces, conceal (and render tamperproof) important attachment fasteners, cover uneven rough openings, and add a decorative flourish.
The plate on the edge of a door (where a bolt or door plunger protrudes) is called the "faceplate";[23] opposite on the jamb is the "latchplate", creating or reinforcing the hole receiving a latch, bolt, or plunger.
For this reason, door handles in most American commercial and industrial buildings and in many households are lever-operated, rather than a knob, as the lever does not require a tight grip.
Levers are also beneficial on doors with narrow stile widths where the reduced backset leaves insufficient space to comfortably turn a doorknob.
Handles that lose traction can frequently be repaired by replacing or adjusting the set screw, which prevents them from slipping on the spindle.
Other types of handles, typically used in Europe, slide onto the spindle but are affixed only to the door itself without use of set screws.
In some automobiles, especially luxury vehicles, the door handles may feature a key-less entry pad utilizing either a numerical code, thumb scan or face recognition.
To avoid hand contact, some door handles are designed to be operated by the arm or foot.
